You MUST TAKE THE FINAL, even if you are a senior!!! If you are sick that day, you will have to make it up before you are allowed to graduate!

Transcription

1 LAHS Physics End-of-Year Final Review Problems Your End-of-Year Physics Final covers the material in Physics during semester two. Juniors and Seniors will take Finals on the SAME Senior Final day so no-one has more of an advantage. The Final has TWO parts. You will have 90 minutes to complete the following: Part I - Free Response Question, it will be one of the following 20 questions, you will solve one on your own. Part II - Multiple Choice Questions. Your Semester grade will be calculated as follows: Quarter 3 grade => 40% of grade Quarter 4 grade => 40% of grade Semester 2 Final Part I and II => 20% of grade Total =>100% You MUST TAKE THE FINAL, even if you are a senior!!! If you are sick that day, you will have to make it up before you are allowed to graduate! Part I - 1 Free Response Questions to be completed individually The purpose of this section is to assess your individual ability to be a Self Directed Learner, a Responsible Individual and your ability to demonstrate your Critical Thinking Skills. Of the Free Response Review Problems in this packet, a set of 6 will be announced in class on Monday June 4th, On the day of your final, you will be asked to write the perfect solutions to one of these six problems chosen at random. The Free Response problem on the exam will be graded with partial credit because the process of Problem Solving is important for anything in life and we want to know if you can demonstrate that process clearly. Point distributions within a particular problem will depend on the difficulty and concepts used to solve the problem. Generally, points will be awarded for the following: 1. clear diagram (even if given in the original problem) with all given initial conditions 2. writing the correct concept equation(s) to be used in solution 3. correct mathematical, symbolic manipulations and algebraic substitutions (if necessary) 4. the correct numerical answer including units of measure. 5. a box highlighting your answer and a brief explanation of its meanings. Part II - Multiple Choice Questions The purpose of this section is to assess your physics knowledge and your ability to apply problem solving strategies that we have learned all year. The questions are mostly conceptual, some mathematical with the purpose of assessing how well you understand the concepts discussed throughout the year similar to the Practice Multiple Choice questions distributed via the class website. Some of the MC questions will come directly from all of the Free Response review packet problems with different variable values. You ll have to work out the problems and choose the best answer from the Multiple Choice answers. Approximately Multiple Choice questions will be on the Final Exam. 1

2 Physics Final Exam Free Response Review Questions 1. A 1055-kg van, stopped at a traffic light, is hit directly in the rear by a 715-kg car traveling with a velocity of m/s. Assume that the van can move freely, as its transmission is in neutral. What is the final velocity of the (a) car and the (b) van. The collision is elastic. 2. A 50.0-kg skater is traveling due east at a speed of 3.00 m/s. A 70.0-kg skater is moving due south at a speed of 7.00 m/s. They collide and hold on to each other after the collision, managing to move off at angle? south of east, with a speed of v f. Find (a) the angle and (b) the speed v f, assuming that friction can be ignored. 3. A piece of glass has a temperature of 83.0 C. Liquid that has a temperature of 43.0 C is poured over the glass, completely covering it, and the temperature at equilibrium is 53.0 C. The mass of the glass and the mass of the liquid are the same. Ignoring the container that holds the glass and liquid and assuming that all heat lost or gained by the surroundings is negligible, determine the specific heat capacity of the liquid. c of glass is 840 J/(kg * C). 4. A lead object and a quartz object each have the same initial volume. The volume of each increases by the same amount, due to a temperature increase. If the temperature of the lead object increases by 4.0 C, by how much does the temperature of the quartz object increase? ß for lead is 87 x 10-6 (C ) -1 and for quartz it is 1.5 x A person s body is covered with 1.0 m 2 of wool clothing. The thickness of the wool is 2.0 x 10-3 m. The temperature at the outside surface of the wool is 11 C, and the skin temperature is 36 C. How much heat per second does the person lose due to the conduction (Q/t). 6. When one gallon of gas is burned in a car engine, 1.19 x 10 8 J of internal energy (U) is released. Suppose that 1.00 x 10 8 J of this energy flows directly into the surroundings (engine block and exhaust system) in the form of heat. If 6.0 x 10 5 J of work is required to make the car go one mile, how many miles can the car travel on one gallon of gas? 7. General Wave questions A. Draw 3 complete cycles of a wave with frequency 60 Hz with an amplitude of 4 m. B. What is the amplitude of a wave that is half as loud as the wave you have drawn above? C. What is the period of a wave that is three times the frequency as the wave you have drawn above? D. Would you be able to hear a wave that has half the frequency you drew above? Why or why not? E. If you were asked to make an closed piped wind instrument with its resonating fundamental frequency of 60 Hz, how long would the pipe have to be? F. If an open pipe had a length of 1.2 meters, what would be the wavelength of the fundamental frequency? 8. Suppose that electrical attraction, rather than gravity were responsible for holding the Earth in orbit around the Sun. If equal and opposite charges Q were placed on the Earth and the 2

3 Sun, what should be the value of Q be to maintain the present orbit? (Hint: treat the Earth and Sun as point charges.) 9.0 Suppose you plugged into the wall outlet a configuration of electric appliances as represented by the resistors in the circuit diagram shown below. A. Find the equivalent total resistance of the circuit shown below. 15? 10 V 30? 10? 6? 4? 20? 40? B. In the circuit diagram above, draw in an ammeter to measure the current from the battery. C. Determine what the ammeter would read for this circuit. D. In the circuit diagram above, draw in a voltmeter to measure the voltage across the 15? resistor. Determine what the voltmeter would read for this circuit. E. Determine the voltage across the 30 and 10? resistors. F. Determine the voltage across the combination of the 15, 20 and 40? resistors. G. Determine the current through the 40? resistor. H. How much power is dissipated by all the resistors in the circuit shown above? I. How much power is supplied by the power source in the circuit shown above? 10. Robert wants to build a stun gun to shock his sister. He knows that any more than 20 milliamps of current can cause permanent physical damage to human beings. If Robert uses the household power outlet ( Amps) and a transformer with 50 primary turns, how many secondary turns does the transformer need and what is the secondary voltage if he wants to shock his sister with 20 milliamps? 11. Predict the mass of the Earth given that the Moon s orbital radius is 3.84 x 10 8 meters and its orbital period is 27.3 days. 12. Two wires are parallel, and one is directly above the other. Each has a length of 50.0 m and a mass per unit length of kg/m. However, the tension is wire A is 6.00 x 10 2 N, and the tension in wire B is 3.00 x 10 2 N. Transverse wave pulses are generated simultaneously, one at the left end of wire A, and the other at the right end of wire B. The pulses travel towards each other. How much time does it take until the pulses pass each other? ( x=v a t=v b t). 3

4 13. Under the floor of your physics room there are 10,000 coils of current carrying wire wrapped around the perimeter of the room. Placed interior to the coils, an iron sheet used to magnetify (the magnification of the magnetic field) B field to strength of Tesla pointing straight up towards the ceiling. Mr. Florendo wants to walk across the room with a 1-meter conducting bar and induce an EMF. Which way does the bar have to be oriented to induce an EMF? Mr. Florendo s radio needs 12 volts of electric potential to operate his radio. If he hooks the radio up to the bar, how fast does he have to walk across the room to make it work? 14. Several questions about EM Induction. A. Explain what is electromagnetic induction. How and what is produced with EM Induction? What are 3 applications of EM Induction? B. Describe the similarities and differences between a simple electric motor and an electric generator. C. In detail, describe a transformer, its purpose, how it achieves its purpose, and its applications. D. Suppose you needed a 40-volt source but had no power source other than the wall outlet which has voltage of 120 V. You do, however, have materials available to make a transformer. E. Describe and draw a picture of the transformer you would build to transform the wall outlet 120 V to the needed 40 volts. F. Suppose you are successful in constructing your transformer. You connect the primary coil to the 120 V power source and connect its secondary coil to a small motor. If your motor dissipates 20 Joules of energy every second, what is its resistance? G. How much current is flowing through the secondary coil? 15. In the figure below, the central particle with charge q = -1 µc is surrounded by two circular rings of radii 1.5 cm and 2 cm containing stationary charged particles,. +4q -2q +2q -2q +q -7q +q -2q +2q -2q a) What s the magnitude of the NET electrostatic force on the central particle due to the other particles? b) What s the direction of the NET electrostatic force on the central particle due to the other particles? c) If the mass of the central particle is the mass of an electron, calculate the initial acceleration of the particle due to the net electrostatic force 4

5 16. A coil of wire has current flowing through it. A second coil is moved away from the first coil. Loop 1 Loop a) What is the direction of the current in loop 1? CW or CCW b) Why does an induced current flow in loop 2? c) What is direction of the induced current in loop 2? CW or CCW Explain in detail or indicate in the picture above how you determine your answer. d) What are at least 3 ways you could increase the current in loop 2? e) Where does the energy come from to make the current flow in loop 2? v External force pushes loop 2 to the left 17. Draw all your ray diagrams for the following problem on the sheet with the following lens and object configurations already printed on it. A. Shown below is a concave mirror with an object. Correctly draw the image formed by the mirror. Object C Virtual or Real? 5

6 B. Shown below is converging lens. Correctly draw the image formed by the lens. Virtual or Real? Object f f 18. The security alarm on a parked car goes off and produces a frequency of 960 Hz. The speed of sound is 343 m/s. As you drive toward this parked car, pass it, and drive away, you observe that the frequency changes by 95 Hz. At what speed are you driving? 19. A string of length 0.28 m is fixed at both ends. The string is plucked and a standing wave is set up that is vibrating at its second harmonic. The traveling waves that make up the standing wave have a speed of 140 m/s. What is the frequency of vibration? 20. Two coils have the same number of circular turns, and carry the same current. Each rotates in a magnetic field. Coil 1 has a radius of 5.0 cm, and rotates in a 0.18-T field. Coil 2 rotates in a 0.42 T field. Each coil experiences the same maximum torque. What is the radius of coil 2? 6